Pearson made a longcurve that didn't have a shelf. It used small plastic dog eared tabs to accommodate this. I've got one in 25#. I didn't like the dog ears so I whittled a shelf out of osage
, stuck it on with contact cement and wrapped the grip with leather. This worked really well once you adjust for shooting that far off center. I can switch it from left to right as needed. I have seen a bow in pictures that has a double shelf, but can't remember who made it; I think Bear or Stemmler.
I also had a fiberglass Martin that shoots both sides its only 20#. Basically the same as the Pearson jet bows: solid glass. With the help of a guy in Ft Worth and a couple members of the LSBA here I was able to give 10 of these to the Sol Mayer scout camp near Menard. The guy in FW said not to tell who he is. This guy likes building bows out of osage suckers.
I know this doesn't answer your question, but thought I'd throw it up there anyway.